OK. I'll give it a go.
As you already know it is a Slogan, rather than a commercial domain. I think it could have visual appeal with the use of the Strike-through often seen when a zero is presented, certainly far more eye-catching. Unfortunately only your .Com is registered and I'm not sure that in this instance that is the strongest extension. Some take-up on the use of 'ZERO' instead of 0 which would be the natural type-in.
I really don't see it having much if any value above maybe a few hundred dollars to a developer looking to run a T-shirt campaign rather than a site of any substance.